Performance regulating device for fluid machinery

ABSTRACT

An apparatus for controlling performance of a fluid machinery by controlling rotational speed of the fluid machinery. A performance regulating device for the fluid machinery includes a frequency converter, a casing for housing the frequency converter so as to ensure being airtight against an atmosphere, an input, and an output connected to the casing so as to ensure being airtight against the atmosphere.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a performance regulating device for afluid machinery, more particularly to a performance regulating devicefor a fluid machinery, which is suitably used for the pump forcirculating cool or hot water.

2. Discussion of the Background

The method for controlling rotation speed of a motor pump through aninverter device (frequency converter) is well known in the art. Thismethod can be very effective means for energy saving in the applicationof the pump for supplying water and so on in which a violent fluctuationof load is occurred, as well as in the application of the pump forcirculating water.

A general purpose pump is not manufactured according to a specificstandard specification, but is selected according to requiredspecification. Namely, the general purpose pump is not order-madeproduct which satisfy a specific specification (flow rate, pump head),but is selected from inventory for use so as to satisfy the scheduledspecification. Additionally, the scheduled specification is generallycalculated so as to satisfy a maximum flow rate in view of enough marginof expected flow rate. The head loss of the piping will be determined inview of enough margin and aged deterioration. Accordingly, when the pumpis operated actually, the valves are controlled for suppressing the overflow rate, thus resulting to a waste of the energy. Even if the pump isselected in accordance with a calculation with calculating formulae,more or less waste of energy will be occurred.

In order to save energy, it is necessary to operate the pump inaccordance with the “true” specification, thus realizing effectiveoperation of the pump without energy loss. The “true” specification isonly acquired after actual operation of the pump is carried out on thesite, where actually required lowest flow rate and pump head can befound merely by operating the pump.

When it is found by the operation of the pump on the site that thecapacity of the pump is too large, the energy can be saved by thefollowing countermeasures:

(1) exchanging the pump with a pump of one rank reduced capacity; and

(2) reducing the outer diameter of the impeller to reduce theperformance of the pump to the suitable value.

However, these countermeasures require additional cost, and it isdifficult to retrieve the performance of the pump of thus reducedperformance. On the contrary, the inverter device can control theperformance of the pump easily and retrievably, so that the pump can beoperated to save energy in accordance with the situation of the sitewithout requiring above mentioned countermeasures.

In a case of incorporating an inverter device into an existing pump on asite, the energy can be saved by the following manners, which hasadvantages and disadvantages as follows:

(1) A Method for Controlling the Existing Motor Pump by AdditionallyInstalled Inverter

(Advantage)

It is unnecessary to alter the motor pump itself.

(Disadvantage)

Generally, the circumstances in which the pump is installed are humidand unsuitable for additionally installing the inverter device. In thisview point, it is preferable to incorporate the inverter device into thecontrol console for controlling the motor pump. It is thus necessary tomodify the existing control console or to construct new control consolefor incorporating the inverter device.

(2) A Method for Exchanging the Existing Motor Pump with a Motor PumpIncorporating an Inverter Device

(Advantage)

Any modification of the control console is substantially unnecessary.

(Disadvantage)

In this method, it is necessary to exchange the motor pump wholly. Theexchanging of the existing pump before reaching the end of its servicelife is disadvantageous in respect of the cost.

(3) A Method for Exchanging the Motor Portion of the Existing Pump witha Motor Incorporating an Inverter Device

(Advantage)

Only exchanging the motor portion is required. However, disassemblingoperation and reassembling operation of the pump portion is alsorequired except for a pump of directly coupling type. It issubstantially unnecessary to modify the control console.

(Disadvantage)

Exchanging of the existing motor before the limit of its service life isdisadvantageous in respect of the cost.

SUMMARY OF THE INVENTION

In view of the above mentioned problems, the present invention providesa technology that performance regulating of pump is easily carried out,and the energy to be consumed thereby is reduced. Namely, it is anobject of the present invention to provide a performance regulatingdevice for fluid machinery that without requiring any modification orchange of existing pumps or existing control consoles, merely adding aninverter device can enable performance regulating of the pumps so as tosave energy.

To achieve above object, according to an aspect of the presentinvention, there is provided.

In accordance with the present invention, the frequency converter issealed completely against the atmosphere, so that the humidity aroundthe pump and the rain do not affect the frequency converter. Further,the degradation of the insulation resistance due to the condensation ofwater within the casing can be avoided, even if the water coolingstructure as mentioned below is adopted.

The submerged cable may be used as input means and output means. In suchcable, the clearance between the core and the insulation is sealedhermetically, and the clearance between the insulation and the coveringis also sealed hermetically.

The present invention is most effective when the fluid machinery is amotor pump of turbo type. The condensation of water can be avoided whenthe frequency converter is cooled by liquid to be handled by the pump.The condensation of water may be occurred with the casing due to coolingby the circulation of the cooled water especially in summer season.Further, an air cooling fan used in the general purpose inverter deviceis not required.

According to an aspect of the present invention, heat radiating means isprovided for transferring a heat generated by the frequency converter toa pipe to be connected to the pump through the surface of the pipe. Thusthe heat generated by the frequency converter can be radiated to thefluid, which is handled by the pump.

According to an aspect of the present invention, heat radiating means isprovided on the casing, and a flow passage is provided through the heatradiating means for passing a fluid to be handled by the pump. At aresult, the heat generated by the frequency converter is radiatedeffectively by the fluid, which is handled by the pump.

According to an aspect of the present invention, heat radiating means isprovided on a casing, and a flow passage is provided through said heatradiating means for passing a fluid, which is handled by the pump. Here,heat radiating means is a water cooling heat sink of stainless steel towhich the liquid to be handled by the pump is introduced through abypass pipe (tube).

According to an aspect of the present invention, a heat radiating plateof air cooling type is provided on the casing of the frequencyconverter. The heat radiating means can be formed by the coupling guardmade of aluminium alloy. Air stream generated by the rotation of thecoupling is directed to flow against the coupling guard to cool it. Thecoupling guard is provided with a plurality of air cooling fins.

According to an aspect of the present invention, a switch is provided bywhich the output frequency can be varied in stepwise manner, for examplein 8 steps by 5% each. At a result, the switch allows the user toregulate the performance of the fluid machinery easily. The switch isnot a volume control dial of analogue type, so that the switchingbetween steps can reliably be effected. When the volume control dial isemployed, means for displaying the output frequency, for example, aliquid crystal monitor is required. Namely, control operation of thevolume control dial does not show real operational condition of thepump, for example, rotational speed of the pump. On the other hand, thestepwise switch select one of the positions hereof corresponding to thepreliminary certified operational condition, so that the performance ofthe pump can be regulated reliably, easily, and reproducibly.

According to an aspect of the present invention, the casing for housingthe frequency converter is commonly used with a frequency converterassembly to be mounted on the outer surface of the pump and cooled bywater. At a result, a pump with inverter device can be delivered to theapplication of newly constructed pumping facility. With respect to theexisting pumping facility before limit of its service life, theperformance regulating device as an flow rate control means can besupplied to the market with high productivity and low cost.

According to an aspect of the present invention, the performanceregulating device is constructed that the frequency converter begins tooutput electrical power automatically when electric power is suppliedthereto. This means that the fluid machinery can be started merely bymaking the power switch “on” on the control console, so that theperformance regulating device can be mounted anywhere, when the deviceis mounted on a pipe. For example, the regulating device can be mountedwith taking the children's play into consideration, or can be mounted ata narrow limited space.

The present invention can be utilized not only as a performanceregulating device for a fluid machinery, but also as a frequencyconverter for controlling the rotational speed of general machineincluding a motor. Further, the device of the present invention caneffectively be used in the out door condition of under rain weathersince the casing is sealed hermetically.

The frequency converter of the present invention does not require an aircooling fan, which is used in the general purpose inverter. Thus,malfunction of the fan can be avoided, and stop of cooling is prevented.

In the second embodiment of the present invention, there is provided aperformance regulating device for a fluid machinery comprising afrequency converter, typically an inverter device, a casing for housingthe frequency converter, input means and output means connected to thecasing, and an output frequency regulating device, wherein the casing ofthe performance regulating device for the fluid machinery is of weatherproof structure avoiding the ingress of the rain water into the casing.

The inverter devices of relatively small output are often of air coolingwithout blower type. These inverter devices does not require the watercooled structure, so that no countermeasures against the condensation ofwater is required. However, the pumping facility are often provided onthe out door condition, so that it is desirable to make the inverterdevices to have weather proofness.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the present invention and many of theattendant advantages thereof will be readily obtained as the samebecomes better understood by reference to the following detaileddescription when considered in connection with the accompanyingdrawings, wherein:

FIG. 1 is a side view of the arrangement of the first embodiment inwhich the performance regulating device for fluid machinery of thepresent invention is employed;

FIG. 2 is a side view of the arrangement of the second embodiment inwhich the performance regulating device for fluid machinery of thepresent invention is employed;

FIG. 3A is a detailed elevational view in partly cross section of thearrangement as shown in FIG. 1, and FIG. 3B is a detailed side view ofthe arrangement as shown in FIG. 1;

FIG. 4 is a cross sectional view taken along line IV—IV as shown in FIG.3A;

FIG. 5A is a detailed elevational view in partly cross section of thearrangement as shown in FIG. 2, and FIG. 5B is a detailed plan view ofthe arrangement as shown in FIG. 2;

FIG. 6 is a cross sectional view taken along line VI—VI as shown in FIG.5A;

FIGS. 7A and 7B are views of the arrangement of the third embodiment inwhich the performance regulating device for fluid machinery of thepresent invention is employed, FIG. 7A is a side view showing the wholeconstruction of the fluid machinery, and FIG. 7B is an elevational viewseen from the direction of the arrow VII;

FIGS. 8A and 8B show another embodiment of the device as shown in FIGS.1-7B, FIG. 8A is an elevational view, and FIG. 8B is a side view;

FIG. 9 is a cross sectional view showing an inline pump of afull-circumferential-flow type pump to which the frequency converterassembly is incorporated. The incorporated assembly includes elements incommon with those of the performance regulating device for fluidmachinery of the present invention;

FIG. 10 is a cross sectional view taken along line X—X as shown in FIG.9;

FIG. 11 is a plan view showing a bracket;

FIG. 12 is a longitudinal cross sectional view showing anotherembodiment of the present invention;

FIG. 13A is an elevational view showing the appearance of the regulatingdevice, and FIG. 13B is a bottom view showing the appearance of theregulating device;

FIG. 14 is a diagrammatic illustration showing the regulating device asillustrated in FIGS. 12, 13A, and 13B, which is installed in a pumpingfacility;

FIGS. 15A and 15B are views of the arrangement of the embodiment inwhich the performance regulating device of naturally air cooling type isattached on a pipe, FIG. 15A is an elevational view in partly crosssection, and FIG. 15B is a side view;

FIGS. 16A and 16B are views of the arrangement of the embodiment inwhich the performance regulating device of water cooling type isattached on a pipe, FIG. 16A is an elevational view in partly crosssection, and FIG. 16B is a side view;

FIGS. 17A and 17B are views of the arrangement of another embodiment inwhich the performance regulating device of water cooling type isattached on a pipe, FIG. 17A is an elevational view in partly crosssection, and FIG. 17B is a side view;

FIG. 18 is an embodiment showing the frequency converter unit and theelectric element unit being connected in series with each other;

FIG. 19 is a view showing another embodiment of the present invention,FIG. 19 is a view corresponding to FIGS. 8A and 8B;

FIGS. 20A and 20B are detailed views of the unit as shown in FIG. 19,FIG. 20A is an exploded view of the unit as shown in FIG. 19, and 20B isa perspective view of the thin plate 90;

FIG. 21 is a side view showing another embodiment of the performanceregulating device of water cooling jacket type; and

FIGS. 22A and 22B are detailed views showing another embodiment formounting the performance regulating device. FIG. 22A is an elevationalview and FIG. 22B is a side view.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A performance regulating device for a fluid machinery according to anembodiment of the present invention will now be described with referenceto the drawings.

The first embodiment of the performance regulating device, which ismounted on a fluid machinery in accordance with the present invention isshown in FIG. 1. A pump unit designated by reference numeral 101comprises a pump 103 and a motor 104 mounted on a common base 102. Thefluid introduced through a suction pipe 105 flows through a gate valve106 provided on a suction side and a short pipe 107, and via an inletport 103 a of the pump into the pump 103, and increased in its pressureby the pump, and then delivered from an outlet port 103 b of the pump.The delivered fluid is then introduced to a delivery pipe 110 through ancheck valve 108 and a gate valve 109 provided on a discharge side.

The performance regulating device (referred to as the regulating devicehereinbelow) 111 for a fluid machinery is mounted on the short pipe 107through a heat radiating means 112 of aluminium alloy, which has goodthermal conductivity.

In the arrangement of this embodiment, the heat radiating means 112 isfixedly secured to the regulating device 111 through bolts (not shown),and fixedly secured on the short pipe 107 by U-bolts (not shown).

Electric power supplied from a control console 113 is applied from aninput cable 114 as an input means of the regulating device 111 to afrequency converter in the regulating device 111, which converts thefrequency of the supplied electric power. The electric power whosefrequency has been converted is supplied from an output cable 115 as anoutput means of the regulating device 111 to the electric motor 104. Thefrequency converter in the regulating device 111 causes a heat loss,which is radiated into the liquid handled by the pump via the heatradiating means 112 and the short pipe 107.

The second embodiment of the regulating device, which is mounted on afluid machinery in accordance with the present invention is shown inFIG. 2. A pump unit designated by reference numeral 101 comprises a pump103 and a motor 104 mounted on a common base 102. The fluid introducedthrough a suction pipe 105 flows through a gate valve 106 provided on asuction side and a short pipe 107, and via an inlet port 103 a of thepump into the pump 103, and increased in its pressure by the pump, andthen delivered from an outlet port 103 b of the pump. The deliveredfluid is then introduced to a delivery pipe 110 through an check valve108 and a gate valve 109 provided on a discharge side.

Electric power supplied from a control console 113 is applied from aninput cable 114 as an input means of the regulating device 111 to afrequency converter in the regulating device 111, which converts thefrequency of the supplied electric power. The electric power whosefrequency has been converted is supplied from an output cable 115 as anoutput means of the regulating device 111 to the electric motor 104.

In the second embodiment of the present invention as shown in FIG. 2,the heat radiating means 112 comprises of a water cooled jacket ofstainless steel secured to the regulating device 111 by means of bolts(not shown). The heat radiating means 111 is fixedly secured through aL-shaped fixture on the flange of the short pipe 107 by a bolt employedin connecting the short pipe 107 to the gate valve 106. A fluid isintroduced into the heat radiating means 112 through a small pipe 117from the discharge side of the pump. The fluid is then bypassed througha small pipe 118 into the suction side of the pump.

In this embodiment, the heat loss produced inevitably with the frequencyconversion is radiated through the heat radiating means 112 and smallpipes 117, 118 into the fluid handled by the pump.

In the arrangement as shown in FIG. 2, a thermal insulation is providedas shown by a dotted line 119. According to the thermal insulation, heatmoving phenomena from the surface of the pipes into ambient air isprevented in circulating system of cooled or heated water and so on.While it is difficult to adopt the regulating device of first embodimentshown in FIG. 1, since it is not appropriate to mount the regulatingdevice 111 within the thermal insulation 119, thus the regulating deviceof the second embodiment is effective on such application having thermalinsulation.

FIGS. 3A and 3B show the regulating device shown in FIG. 1 in detail.FIG. 3A is a front elevational view, partly in cross section, of theregulating device, and FIG. 3B is a side elevational view of theregulating device.

The heat radiating means 112 is fixed to the short pipe 107 by U-bolts120. The input cable 114 and the output cable 115 keep the regulatingdevice 111 hermetically sealed from the atmosphere in the same manner aswith an underwater cable of a submersible motor pump, for example. AnO-ring 121 is disposed to prevent ambient air from entering theregulating device through the mating surface between the heat radiatingmeans 112 and the regulating device 111.

A structure around the regulating device 111 will be described belowwith reference to FIG. 4 which is a cross-sectional view taken alongline IV—IV of FIG. 3A. The frequency converter 48 is housed in a casewhich comprises the base 46 and the cover 47. The base 46 and the cover47 made of aluminium alloy having good thermal conductivity are fixed toeach other by bolts with a seal member 58 interposed therebetween forhermetically sealing from the ambient air. As shown in FIG. 4, the inputcable 114 is connected to the base 46, and as shown in FIG. 3A, theoutput cable 115 is also connected to the heat radiating means 112.

The frequency converter 48 is highly intimately fixed to the base 46 totransfer the generated heat to the base 46. Similarly, the base 46 andthe heat radiating means 112, and the heat radiating means 112 and theshort pipe 107 are highly intimately fixed to each other. Since the heatgenerated by the frequency converter is suitably radiated into thehandled fluid, the regulating device does not require an air-cooling fanfor use in general inverters. Thus, the regulating device is free frominsufficient cooling due to a fan failure. The base 46 and the heatradiating means 112 are fastened to each other by bolts 55. Because theinterior of the case is isolated from the ambient air, the frequencyconverter is prevented from insulation deterioration due to weatheringand water condensation.

FIGS. 5A and 5B are illustrations showing the arrangement shown in FIG.2 in detail. FIG. 5A is a partly cross sectional elevational view, andFIG. 5B is a plan view. The heat radiating means 112 comprises of awater cooling jacket of stainless steel. The jacket is provided with anoutlet or inlet port 122 for passing the fluid to be handled. Thestructure of the input cable, the output cable, and the O-ring 121 arethe same structure as shown in FIG. 3A.

The peripheral structure of the regulating device 111 of this embodimentwill now be described with reference to FIG. 6 which is a crosssectional view taken along line VI—VI as shown in FIG. 5A. The frequencyconverter 48 is accommodated within a casing formed by a base 46 and acover 47. The base 46 is secured to the cover 47 by bolts (not shown)with interposing a sealing member 58 for preventing the ingress of anambient air.

The frequency converter 48 itself is secured tightly on the base 46 totransfer the generated heat thereto. The base 46 is also secured tightlyon the heat radiating means 112. Thus, the heat generated by thefrequency converter is radiated well into the fluid to be handled, sothat a cooling system such as an air cooling fan used in the generalpurpose inverter device is not required.

The ribs 123 have three functions. The one of the functions is toincrease the strength and the rigidity of the water cooling jacket toprevent deformation thereof. The other function is to guide the flow ofthe fluid through the jacket to assure the residence time of the fluidto be handled. Further function of the ribs is to increase thecontacting area between the ribs and the fluid to be handled to enhancethe effect of heat radiation. In accordance with the arrangement of thisembodiment, the cooling operation can easily and effectively be carriedout in spite of existence of the thermal insulation provided aroundpipes.

The third embodiment of the regulating device, which is mounted on afluid machinery in accordance with the present invention will bedescribed with reference to FIGS. 7A and 7B. FIG. 7A is a side viewshowing the whole construction of the fluid machinery, and FIG. 7B is anelevational view seen from the direction of the arrow VII. The basicarrangement of the third embodiment is substantially identical withthose of the first and second embodiments. However, in the thirdembodiment, there is provided an air cooled regulating device 111, whichuses air stream generated by the coupling 126 connecting the pump 103and the motor 104.

Generally, a coupling guard for preventing an accident is providedaround the coupling 126 as shown in FIG. 7B. The coupling guard isemployed in this embodiment as the heat radiating means 112.

In this embodiment, the coupling guard (the heat radiating means) 112 ismade of aluminium alloy, and a plurality of air cooling ribs (fins) 128are provided therewith for enhancing the effect of cooling by the airstream. The peripheral structure of the casing is substantiallyidentical with those of the first and the second embodiments, so that itis endurable in its weathering conditions.

Another embodiment of the regulating device will now be described withreference to FIGS. 8A and 8B. FIG. 8A is an elevational view, and FIG.8B is a side view. To explain briefly, the only difference from thoseshown in FIGS. 1-7A is that the output cable 115 is connected to thebase 46.

In this arrangement, the regulating device of relatively simplestructure can be provided, since it is unnecessary to connect the outputcable to the heat radiating means. Of course, the arrangement can beadopted in the arrangement of the water jacket type or the air cooledtype.

In FIGS. 3A and 3B, 5A and 5B, and 8A and 8B, a threaded cap 124 servesto keep the regulating device hermetically sealed from the ambient airthrough an O-ring (not shown). The threaded cap 124 houses thereinadjusting means for output frequency. For example, the adjusting meanscomprises a rotary step switch for enabling to adjust the rotationalspeed of the fluid machinery.

Further, as can be seen in the drawings that there is no designation ofan on-off switch for outputting or stopping the output of the frequencyconverter, the frequency converter has no means corresponding to theon-off switch. The frequency converter is arranged to commence itsoperation to output electric power automatically, when power supply isdelivered thereto. In this connection, there is no limitation upon theposition, when the regulating device is installed on the pipe line. Inother words, since start and stop of the fluid machinery can merely beeffected by starting or stopping the electric power supply thereto, theregulating device can be mounted on any place, for example, at a highplace where children can not reach with taking into consideration ofchildren's brogue or at a narrow space.

With reference to FIGS. 9-11, an embodiment of a pump having aregulating device of the present invention is described, where frequencyconverter is mounted integrally therewith and is used at least as commonuse.

Before describing the embodiment of the FIGS. 9-11, the advantages ofthe converter itself as the common use will be described briefly. By themass production, reduction of the cost can be obtained by providing newpumps incorporating inverter device as shown in FIGS. 9-11 to the newlyconstructed pump facilities, and providing flow regulating devices tothe existing pump facilities, which are not yet to the limit of itsservice life. Accordingly, energy saving devices can be easily acceptedin the market. FIG. 9 is a cross sectional view, which illustrates aninline full-circumferential-flow type pump. The illustrated pump has afrequency converter assembly mounted integrally therewith, which are incommon use with those of the performance regulating device for anexisting fluid machinery in accordance with the present invention. FIG.10 is a cross sectional view taken along line X—X as shown in FIG. 9.

A full-circumferential-flow pump of this embodiment comprises a pumpcasing 1, a canned motor 6 housed in the pump casing 1, and an impeller8 fixedly mounted on a main shaft 7 of the canned motor 6. The pumpcasing 1 comprises an outer cylinder 2, a suction-side casing 3connected to an axial end of the outer cylinder 2 by flanges 61, 62, anda discharge-side casing 4 connected to an opposite axial end of theouter cylinder 2 by flanges 61, 62. The flanges 61 and 62 constitutefixing means for fixing another member such as the suction-side casing 3or the discharge-side casing 4 to the outer cylinder 2. Each of theouter cylinder 2, the suction-side casing 3, and the discharge-sidecasing 4 is made of a pressed sheet of stainless steel or the like.

A bracket 45 is attached to the outer surface of the outer cylinder 2. Aregulating device 50 is mounted on the bracket 45. The regulating device50 comprises a base 46 attached to the bracket 45, a cover 47 attachedto the base 46, and a frequency converter 48 housed in the base 46 andthe cover 47.

The bracket 45 has a through hole 45 a for allowing leads for connectingthe canned motor 6 and the frequency converter 48 to pass therethrough.The bracket 45, the base 46 and the cover 47 are composed of thermallygood conductor such as aluminum alloy. The bracket 45 has a through hole45 b for allowing cooling water for cooling the frequency converter 48to pass therethrough.

The canned motor 6 comprises a stator 13, an outer motor frame barrel 14fixedly fitted over the stator 13, a pair of motor frame side plates 15,16 welded to respective opposite open ends of the outer motor framebarrel 14, and a can 17 fitted in the stator 13 and welded to the motorframe side plates 15, 16. The canned motor 6 also has a rotor 18rotatably disposed in the stator 13 and shrink-fitted over the mainshaft 7. An annular fluid passage 40 is formed between the outer motorframe barrel 14 and the outer cylinder 2.

Further, a guide device 11 for guiding fluid from a radially outerdirection toward a radially inner direction is held by the motor frameside plate 16. An inner casing 12 for housing an impeller 8 therein isfixed to the guide device 11. A sealing member 13 is provided on theouter periphery of the guide device 11.

A liner ring 51 is mounted on a radially inner end of the guide device11 and is in slide contact with the forward end (suction mouth) of theimpeller 8. The inner casing 12 has a dome-like shape so that it coversthe end of the main shaft 7 of the canned motor 6. The inner casing 12has a guide device 12 a comprising a guide vane or a volute for guidingfluid discharged from the impeller 8. The inner casing 12 has a venthole 12 b at the forward end thereof.

A cable housing 20 is welded to the outer motor frame barrel 14. Leadsfrom coils disposed in the outer motor frame barrel 14 are extendedthrough the cable housing 20, the through hole 45 a of the bracket 45and a lead hole 46 a of the base 46, and connected to the frequencyconverter 48 in the base 46 and the cover 47. Further, a cable 63 isintroduced into the base 46 and connected to leads of the frequencyconverter 48 in the base 46 and the cover 47. The outer cylinder 2 has ahole 2 a into which the cable housing 20 is inserted.

Next, a bearing assembly at the impeller side will be described. Aradial bearing 22 and a stationary thrust bearing 23 are mounted on abearing bracket 21. The radial bearing 22 has an end which serves as astationary thrust sliding member. A rotary thrust bearing 24 and arotary thrust bearing 25 each serving as a rotary thrust sliding memberare disposed one on each side of the radial bearing 22 and thestationary thrust bearing 23. The rotary thrust bearing 24 is secured toa thrust disk 26 which is fixed to the main shaft 7 through a key. Therotary shaft bearing 25 is secured to a thrust disk 27 which is fixed tothe main shaft 7 through a key.

The bearing bracket 21 is inserted in a socket defined in the motorframe side plate 16 through a resilient O-ring 29. The bearing bracket21 is also held against the motor frame side plate 16 through aresilient gasket 30. The radial bearing 22 slidably supports a sleeve 31which is fitted over the main shaft 7.

Next, a bearing assembly at the opposite side of the impeller will bedescribed. A radial bearing 33 is mounted on a bearing bracket 32, andslidably supports a sleeve 34 which is fitted over the main shaft 7. Thesleeve 34 is axially held against a washer 35 which is fixed to the mainshaft 7 by a double nut 36 threaded over an externally threaded surfaceon an end of the main shaft 7. The bearing bracket 32 is inserted in asocket defined in the motor frame side plate 15 through a resilientO-ring 37. The bearing bracket 32 is also held against the motor frameside plate 15. Stays 43 are welded to the outer motor frame barrel 14,and the stays 43 and the outer cylinder 2 are welded together. Therotational speed of the canned motor is set to 4,000 rpm or more by thefrequency converter 48.

Operation of the full-circumferential-flow pump shown in FIG. 9 will bedescribed below.

A fluid drown into the suction-side casing 3 from the suction nozzle 3 aflows into the annular fluid passage 40 defined between the outercylinder 2 and the outer motor frame barrel 14 through the suction-sidecasing 3. Then, the fluid is introduced into the impeller 8 through theannular fluid passage 40 and the guide device 11. The fluid dischargedfrom impeller 8 is discharged through the guide device 12 a from thedischarge nozzle 4 a which is connected to the discharge-side casing 4.

According to this embodiment, the bracket 45 is provided between theregulating device 50 and the outer cylinder 2 of the pump casing 1. Thebracket 45 serves as a dimension adjustment member, and is dimensionedsuch that it is smaller than the base 46 of the regulating device 50.The bracket 45 is a small component, and hence the preparation of manykinds of brackets does not lead to a lowering of productivity.

As shown in FIG. 9, two fixing members 53 having respective bolts fixedthereto are fixed at a certain interval to the outer cylinder 2 bywelding. On the outer hand, as shown in FIG. 11, the bracket 45 hasnotches 45 c at its both ends. The bracket 45 is fixed to the outercylinder 2 in such a manner that the notches 45 c of the bracket 45 arefitted with the fixing members 53, respectively, and then nuts 54 arefastened to the bolts 52, respectively.

Next, the method for fixing the regulating device 50 to the motor pumpwill be described.

First, the regulating device 50 is independently assembled by housingthe frequency converter 48 in the base 46 and the cover 47. After theregulating device 50 is assembled, the regulating device 50 and thebracket 45 are fixed to each other. This is preformed by fastening thebolts 55 to the base 46 through the bracket 45. This work can be madefrom the outside of the regulating device 50. After the bracket 45 andthe regulating device 50 are fixed to each other, the notches 45 c ofthe bracket 45 are fitted with the fixing members 53, respectively, andthe nuts 54 are fastened to the bolts, respectively, whereby the bracket45 is fixed to the outer cylinder 2 of the motor pump.

In this manner, the regulating device 50 comprises the base 46 attachedto the bracket 45, the cover 47 attached to the base 46, and thefrequency converter 48 housed in the base 46 and the cover 47.Therefore, the regulating device 50 can be independently assembled. Thefixing of the bracket 45 and the regulating device 50 to each other canbe carried out from the outside of the regulating device 50. Further,after the bracket 45 and the regulating device 50 are fixed to eachother, the bracket 45 can be fixed to the outer cylinder 2. The cover 47and the base 46 are unnecessary to be disassembled from each othernormally, except for maintenance of the frequency converter 48. That is,when the frequency converter is mounted on the pump or removed from thepump, the highly integrated circuit of the frequency converter is notexposed to the outside. This structure is effective because the highlyintegrated circuit or the electrical board is weak in dust or dirt.

According to this embodiment, the bracket 45 has the through hole 45 ato connect the canned motor 6 and the frequency converter 48electrically. Thus, attachment of the regulating device 50 to the motorpump can be made with ease.

According to this embodiment, the bracket 45, the base 46 and the cover47 are composed of thermally good conductor, i.e., aluminum alloy. Sincethe frequency converter of this kind is mainly cooled by a liquidhandled by the pump, aluminum alloy is preferable. The above members aremade of metal to thus shield radiation noise from the frequencyconverter. Especially, the bracket is made of metal to thus shieldharmonic noise generated in the secondary side of the frequencyconverter.

Further, according to this embodiment, the bracket 45 has the throughhole 45 b for allowing cooling water to pass therethrough. The frequencyconverter is normally cooled by a liquid handled by the pump. If theliquid handled by the pump has high temperature, the frequency convertercannot be cooled by the pumped liquid. In such a case, cooling liquidcan be supplied from the outside to the though hole 45 b of the bracket45 to cool the frequency converter sufficiently.

According to this embodiment, heat transfer medium is interposed betweenthe outer cylinder 2 and the bracket 45, between the bracket 45 and thebase 46, and between the base 46 and the cover 47. If a clearance isformed between two members, air is in the clearance to prevent heattransfer between two members, resulting in inferior cooling. Therefore,heat transfer medium such as liquid silicon is charged into theclearance to improve heat transfer between two members.

According to this embodiment, sealing members 56, 57 and 58 are providedbetween the outer cylinder 2 and the bracket 45, between the bracket 45and the base 46, and between the base 46 and the cover 47, respectively.Thus, moisture is prevented from entering the case housing the frequencyconverter 48, and the frequency converter is not deteriorated due to dewformed by moisture when cooled by the liquid handled by the pump.

Further, according to this embodiment, in the pump assembly comprisingthe outer motor frame barrel 14 provided around the stator 13 of thecanned motor 6, the outer cylinder 2 defining the annular fluid passage40 between the outer motor frame barrel 14 and the outer cylinder 2, apump section including the impeller 8 for allowing liquid to flow in theannular fluid passage 40, and fixing means comprising the flanges 61 and62 for fixing another member such as the suction-side casing 3 or thedischarge-side casing 4 to the outer cylinder 2, the regulating device50 is mounted on the outer circumferential portion of the outer cylinder2, and both ends of the regulating device are axially extended beyondthe fixing means 61, 62 provided at both ends of the outer cylinder 2.

Another embodiment of the regulating device 111 is illustrated in FIGS.12, 13A, and 13B. FIG. 12 is a longitudinal cross sectional view of theregulating device 111, FIG. 13A is an elevational view showing theappearance of the regulating device 111, and FIG. 13B is a bottom viewshowing the appearance of the regulating device 111.

As can be seen from FIG. 12, the frequency converter 48 is accommodatedwithin a casing formed by a base 46A and a cover 47A. The base 46A andthe cover 47A are made of aluminium alloy having good thermalconductivity, and secured by bolts (not shown) with interposing asealing member 58 therebetween. The frequency converter 48 is securedtightly on the base 46A. The base 46A has a plurality of air coolingfins 46 a on the bottom portion thereof. The fins 46 a are provided foremitting the heat generated by the conversion loss of the frequencyconverter to the atmosphere. The lower surface of the base 46A is alsoprovided with a hole 46 b for introducing air into the casing.

The upper surface of the cover 47A is provided with a ventilation duct71 as shown in FIG. 12. The ventilation duct 71 does not allow theingress of rain water into the casing mostly, but facilitates theventilation of the air freely.

In the arrangement of this embodiment, the heat generated by thefrequency converter (inverter device):

(1) can be radiated by the emission of the heat through the air coolingfins 46 a; and

(2) can be effectively radiated by exchanging the warm or hot air withinthe casing directly with the air of atmosphere.

Namely, since the temperature of the air within the casing is increasedby the generated heat, the specific gravity of the air is reducedthereby, and the air of thus reduced in its density is tend to beascended to the ceiling formed by the cover, and then discharged outthrough the ventilation duct 71. Then, the discharged air within thecasing is refilled by fresh air, which is suctioned through the hole 46b of the base 46A. Thus, the heat generated by the inverter device canbe bleed out efficiently into the atmosphere.

The configuration and the position of the ventilation duct 71 and thehole 46 b for introducing air into the casing can be selectedappropriately so as to meet with attaching manner and direction ofcounterpart member thereof, with which the regulating device 111 ismounted.

In case the rain water is penetrated through the ventilation duct 71, orthe dew is produced within the casing in any reason, the water withinthe casing may be delivered out through the hole 46 b provided throughthe base 46A. In this reason, the arrangement can be used in almost allsites without causing any problem.

Provided that the sufficient cooling effect can be obtained, the casingmay be hermetically sealed. In such a structure, no water can bepenetrated into the casing, even if any direction or any amount of rainfalls.

When a submerged cable is employed as input means or output means of thepower supply, the performance regulating device can be disposed underwater. This arrangement is preferable when the performance of thesubmerged motor pump is controlled under water, and also preferable forcooling the frequency converter.

As can be seen in FIGS. 12, 13A, and 13B, the base 46A is provided withan input cable 114 and an output cable 115 being fixed therewith.

The regulating device as illustrated in FIGS. 12, 13A, and 13B isinstalled for use as shown in FIG. 14. The pump unit is designated bythe reference numeral 101, and includes an inline pump 103A and a motor104A. The fluid introduced through a suction pipe 105 flows through agate valve 106 provided on a suction side and a short pipe 107, and viaan inlet port 103 a of the pump into the pump 103A, and increased in itspressure by the pump, and then discharged from an outlet port 103 b ofthe pump. The discharged fluid is then introduced into a delivery pipe110 through an check valve 108 and a gate valve 109 provided on adischarge side.

The electric power supplied from a control console 113 is input throughan input cable 114 into the frequency converter accommodated within theregulating device 111, and the frequency conversion is carried out. Thecable 114 is connected as input means of the regulating device 111. Theelectric power of thus converted in its frequency is supplied through anoutput cable 115 into the motor 104A. The cable 115 is connected asoutput means of the regulating device 111. The frequency conversioncarried out in the regulating device 111 will inevitably generate a heatloss. However, generated heat loss is in this embodiment emitted throughair cooling fins 46 a, and through exchanging of the warm or hot airwithin the casing (including the base 46A and the cover 47A) with air ofatmosphere directly. Thus the frequency converter can be cooledefficiently.

An embodiment in which a casing housing the frequency converter isattached on the counterpart member by member of straps or strings willbe described with reference to FIGS. 15A-17B.

In the case that the fluid machinery is a submerged pump, it ispreferable to mount the regulating device 111 on a pipe to be connectedto the pump. This is, because a pipe (there is a case of hose) isinevitably connected with the submerged pump, convenient for obtaining aspace for mounting the regulating device 111 thereon.

A regulating device of naturally air-cooling type is shown in FIGS. 15Aand 15B, which is mounted on a pipe. FIG. 15A is a front elevationalview, partly in cross section, and FIG. 15B is a side view. In the caseof naturally air-cooling type, the counterpart member on which theregulating device 111 is to be mounted is not necessarily limited to thepipe, but a tree or a pole, for example, can be used as the counterpartmember.

In this embodiment, fastening bands 72 (e.g. those of sheet metal ofstainless steel) are fixed to the casing by bolts 73, and the bands aretightened on the pipe 75 of the diameter of D by tightening screw 74 asshown in FIG. 15A. When a cushioning material 76 formed such as ofrubber or sponge is interposed between the casing and the pipe 75, thecushioning material will improve the stability thereof upon mounting.

In such method employing the straps, wires, or strings to mount thecasing on the counterpart member, the cumbersome operation for alteringthe already constructed pipe line is not necessary, thus the mountingoperation of the regulating device can be carried out easily.

A regulating device 111 of water-cooling type mounted on a pipe is shownin FIGS. 16A and 16B. FIG. 16A is a front elevational view, partly incross section, and FIG. 16B is a side view. In the embodiment as shownin FIGS. 16A and 16B, the heat generated by the frequency converter isradiated through the surface of the pipe into the fluid to be handled bythe pump. The structure of the fastening bands 72 are the same as thoseshown in FIGS. 15A and 15B.

The direct contact of the casing (including the base 46A and the cover47A) with the pipe is most effective for radiating the heat. In order tocontact the casing with the pipe directly, it is necessary to adjust ofthe shape of the base of the casing to conform to the diameter of thepipe on which the casing is to be mounted. However, preparing varioussizes of performance regulating devices in corresponding with variousdiameters of the pipes will decrease the productivity. In order toovercome such disadvantage, a mounting bracket 80 for functioning as asize adapting member is interposed between the casing and the pipe 75 asshown in FIGS. 16A and 16B. The regulating device 111 of a fixed size(one size) can be mounted through the size adapting member on a pipe ofvarious diameters, such as 32 mm, 40 mm, 50 mm, 65 mm, 80 mm, 100 mm,125 mm, 150 mm, 200 mm.

The bracket 80 can be made of aluminium alloy having good thermalconductivity. In such a case, it is preferred to manufacture the bracket80 by drawing. The longitudinal direction of the drawn bracket 80 iscoincident with the longitudinal direction of the pipe within which thefluid to be handled by the motor pump flows.

The bracket 80 (size adapting member) can also be made of the resinousmaterial to be hardened with time. In such a case, clearances formedbetween elements are filled by injected resin and cured therein afterfastening the casing and the pipe with the fastening bands. The thermalconductivity of the resinous material may preferably be improved byblending metallic powder.

Further, the bracket can be formed of an elastic member such as rubberor a plastic member such as clay having good thermal conductivity.

It is preferred to provide an attaching member such as the band to havea spring effect. The member having spring effect can maintain the casingand the pipe being contacted tightly with each other, even if thetightening screw is loosened. It is also advantageous to form the band(string or wire) with the elastic material such as a rubber.

Another embodiment of a regulating device 111 of the water-cooling typemounted on a pipe is shown in FIGS. 17A and 17B. FIG. 17A is a frontelevational view, partly in cross section, and FIG. 17B is a side view.The illustrated embodiment is a structure of cooling-water type, whichis not applicable for direct heat radiation to the fluid within thepipe. For example, the embodiment is applied in the case that thermalinsulation material such as a lagging is provided around the pipe. Thestructure of the fastening band is the same as that illustrated in FIGS.15A, 15B, 16A, and 16B. A water jacket 81 is interposed between thecasing (including the base 46A and the cover 47A) and the thermalinsulating material 78 provided around the pipe 75, and secured thereon.The frequency converter can be cooled effectively by introducing acoolant into the water jacket 81. A portion of the fluid handled by thepump can be utilized as the coolant, while when the fluid is hot,service water can be introduced therein.

In accordance with the present invention, the same regulating device canbe used with adjusting various conditions of pipes as shown in FIGS.16A, 16B, 17A, and 17B, thus the degree of freedom of mounting isrelatively high.

The weathering proof structure of the device of the present inventioncan be utilized not only as the performance regulating device but alsoas the frequency converter unit. Because, the device can be used inout-of-doors.

The casing employed for housing the frequency converter can be used in avariety of other applications. Generally, troubles may occur on electricelements due to the degradation of the insulation by the rain water orthe humidity. In accordance with the present invention, such trouble canbe avoided by housing electric elements within the sealed casing.

In such cases, the contents of the performance regulating device can bemerely exchanged for other application, thus providing good productivityin view of utilizing common elements or parts.

In some cases, an AC reactor or noise filter is required for reducingthe harmonics or for reducing line noises at the input of the frequencyconverter.

In an embodiment as shown in FIG. 18, the frequency converter unit 200is connected in series with an electric element unit 210 comprising ofthe AC reactor and/or the noise filter.

The casing and the bracket of the frequency converter unit 200 and theelectric element unit 210 are the same structure as shown in FIGS. 16Aand 16B. The frequency converter unit 200 includes the frequencyconverter, and the electric element unit 210 includes the AC reactorand/or the noise filter.

The arrangement of the motor pump and the peripheral structure of thepump are the same as that illustrated in FIG. 1.

When the frequency converter unit (performance regulating device) isconnected between the existing control console and the motor pump, it isoften necessary to take countermeasures against the line noises. Inaccordance with the present invention, it is unnecessary to makemodification on the control console, if it is required to incorporatethe noise filter. The line noises can be reduced or eliminated by theelectric element unit connected in series with the frequency converterunit disposed on the pipe, thus it is very convenient.

The further embodiment of the present invention will now be describedwith reference to FIGS. 19, 20A, and 20B. FIG. 19 is a partly crosssectional view corresponding to FIGS. 8A and 8B. FIGS. 20A and 20B aredetailed view showing a unit of the structure as shown in FIG. 19. FIG.20A is an exploded view showing a unit as illustrated in FIG. 19. FIG.20B is a perspective view of a thin corrugated plate 90. The frequencyconverter 48 is accommodated within the casing formed by the base 46 andthe cover 47. A bracket 80 of aluminium alloy has a curvilinear concavesurface 80 a, which is conformed to the radius of curvature of the pipe75.

However, the radius of curvature (diameter) of the pipe is variedslightly in each pipe due to the manufacturing tolerance or the flaw orthe rust on the surface of the pipe. This variation of the radius ofcurvature of the pipe will form a clearance between the pipe and thebracket, when the bracket is mounted directly on the pipe. The clearancewill cause poor cooling effect, and the degree of cooling effect isvaried in each pipe.

In order to eliminate the clearance effectively, the thin plate 90 isinterposed between the pipe and the bracket. The thin plate 90 is aplate of cupper having a thickness of 0.2-0.5 mm. The plate can easilybe deformed plastically. The thin plate 90 is formed as a thincorrugated plate 90 as shown in FIG. 20A.

After the thin plate 90 is interposed between the pipe and the bracket,the fastening bands 72 (refer FIGS. 17A, 17B) are tightened to increasethe pressure generated on the mounting surface between the pipe and thebracket. The plate is thus deformed under the pressure to eliminate theclearance to connect the bracket thermally with the pipe through thelarger area therebetween. The heat generated by the inverter device canbe transferred effectively to the pipe in spite of the variation of theradius of curvature of the pipe.

In order to enhance the effect of the thin plate, a caulking materialsuch as silicone may be applied on both surfaces of the cupper plate foreliminating the clearance completely to increase the heat transfer. Inorder to reduce irregularity of the application of the silicone, thethin plate 90 is provided with holes 90 a as shown in FIG. 20B. As thedegree of tightening of the bands 72 are increased, the silicone tendsto be spread over both surface of the plate.

Another embodiment of the regulating device 111 of the water-coolingjacket type is shown in FIG. 21.

The regulating device 111 is of a vertical type, and is constructed soas to conform with the diameter of the commercially availablestandardized steel pipe (e.g. SGP). The performance regulating device(frequency converter unit) 111 is mounted around the periphery of thesteel pipe. Namely, a base plate 96 is provided on the one end of thecommercially available standardized steel pipe 95, and an air vent valve97 is provided on the other end of the pipe. The cooling water orcoolant introduced into the steel pipe 95 through the bottom thereofwill absorb the heat from the frequency converter within the regulatingdevice 111, and then flows out through the top portion of the pipe 95.The arrangement of the motor pump and the peripheral equipments aroundthe pump are the same as that illustrated in FIG. 1.

Another embodiment of the method for mounting the performance regulatingdevice 111 is shown in FIGS. 22A and 22B. FIG. 22A is an elevationalview and FIG. 22B is a side view.

L-shaped fixtures 92 are connected to the base 46 of the frequencyconverter by bolts 93. A stopper 92 a is formed on each L-shapedfixtures 92 to avoid the disconnection of the fastening bands 72. TheL-shaped fixtures are formed for example of a plate of stainless steel.The L-shaped fixtures 92 are disposed directing toward the center of thepipe 75 and secured by the bolts 93. The L-shaped fixture 92 is spacedapart at about 2-3 mm from the surface of the pipe 75, so that springaction is given thereby, thus preventing from loosening of the bands.

In accordance with the present invention, a performance regulatingdevice for fluid machinery can be realized, which includes a frequencyconverter as a main element, and which does not affected by the rain ordew in the out-door circumstances, thus contributing to save energy asdescribed above.

The performance regulating device does not require a motor fan forcooling thereto, which is usually required in general inverter devices,thus resulting to improve reliability. Since various cooling means canbe adopted in one regulating device, the regulating device can beinstalled anywhere depending on the circumstance of the sites.

The rotational speed can easily be changed, so that everybody canparticipate in saving energy. In the arrangement of the presentinvention, parts or elements can be used commonly, thus the productivitythereof is high.

The contribution according to the present invention is large for savingenergy, as described above.

INDUSTRIAL APPLICABILITY

The present invention can be suitably utilized in the fluid machinerysuch as a pump for circulating cooled or heated water.

What is claimed is:
 1. A performance regulating device for fluidmachinery, comprising; a frequency converter a pump, a casing forhousing the frequency converter therein so as to ensure airtight againstan atmosphere, input means and output means of electric power providedwith the casing so as to ensure airtight against the atmosphere, anoutput frequency regulating device for controlling an output frequency,and heat radiating means for transferring a heat generated by saidfrequency converter to a pipe to be connected to said pump through asurface of the pipe.
 2. A performance regulating device for fluidmachinery as claimed in claim 1, wherein the fluid machinery comprises amotor pump of a turbo type.
 3. A performance regulating device for fluidmachinery as claimed in claim 2, further comprising; heat radiatingmeans being provided on said casing, and a flow passage being providedthrough said heat radiating means for passing a fluid, which is handledby the pump.
 4. A performance regulating device for fluid machinery asclaimed in claim 1, further comprising; a heat radiating plate for aircooling being provided on said casing.
 5. A performance regulatingdevice for fluid machinery as claimed in claim 1, wherein said outputfrequency regulating device comprises a stepwise control switch.
 6. Aperformance regulating device for fluid machinery as claimed in claim 1,wherein said casing is used in common with said frequency converter,which is mounted on an outer surface of the pump and cooled by water. 7.A performance regulating device for fluid machinery as claimed in claim1, wherein said frequency converter begins to output electrical powerautomatically when electric power is supplied thereto.
 8. A performanceregulating device for fluid machinery, as claimed in claim 1, whereinsaid casing of the performance regulating device for the fluid machineryhas weather proof structure, which is able to avoid at least an ingressof rain water into the casing.
 9. A performance regulating device forfluid machinery as claimed in claim 8, further comprising: means forpreventing condensation of water, which is able to avoid condensation ofwater substantially within the casing.
 10. A performance regulatingdevice for fluid machinery as claimed in claim 8, wherein said casing isformed to ensure airtight against an atmosphere.
 11. A performanceregulating device for fluid machinery as claimed in claim 8, whereinsaid casing has a structure on upper side thereof, in which rain wateris difficult to enter into the casing but air can flow in or out fromthe casing.
 12. A performance regulating device for fluid machinery asclaimed in claim 8, wherein a hole is provided at lower side of thecasing.
 13. A performance regulating device for fluid machinery asclaimed in claim 8, wherein fins are provided for emitting heat on outersurface of said casing.
 14. A performance regulating device for fluidmachinery as claimed in claim 8, wherein said casing is mounted on acounterpart member by elongated members of a strip shape or a stringshape.
 15. A performance regulating device for motor pump as claimed inclaim 8, wherein when the fluid machinery is a motor pump, theperformance regulating device is provided with the motor pump directlyor indirectly, and the casing is mounted on a member, through which afluid to be handled by said motor pump flows.
 16. A performanceregulating device for motor pump as claimed in claim 15, furthercomprising: a mounting bracket for functioning as a size adapting memberbeing interposed between the member through which a fluid to be handledflows and the casing.
 17. A performance regulating device for motor pumpas claimed in claim 16, wherein said mounting bracket is made of analuminum alloy having good thermal conductivity.
 18. A performanceregulating device for motor pump as claimed in claim 16, wherein saidmounting bracket is made of an elastic material.
 19. A performanceregulating device for motor pump as claimed in claim 16, wherein saidmounting bracket is made of an elastic material.
 20. A performanceregulating device for fluid machinery as claimed in claim 16, wherein anattaching member having spring effect is provided for maintaining thecasing and the pipe being contacted tightly with each other.
 21. Aperformance regulating device for fluid machinery as claimed in claim16, wherein the casing is commonly used for the casing of a performanceregulating device.
 22. A performance regulating device for fluidmachinery as claimed in claim 16, wherein an electric element unit and afrequency converter unit are connected in series through the electricpower input means and output means of these units.
 23. A performanceregulating device for fluid machinery as claimed in claim 22, whereinthe electric element comprises an AC reactor for reducing harmonics or anoise filter for reducing line noises.